Electric barometer-switch.



P. E. STOFT.

ELECTRIC BAROMETERSWITCH.

APPLICATION FILED APR. 25' 1916.

Patnted Mar. 20, 1917.

PETER ERNEST STOFT, OF NEW YORK, N. Y.

ELECTRIC BAROMETERSWITCH.

Specification of Iietters Patent.

Patented Mar. 20, 1917.

Application filed April 25, 1916. Serial No. 93,550.

To all whom it may concern.

. Be it known that I, PETER ERNEST Sror'r, a citizen of the .United States, residing at New York city, in the county of Kings and State of New York, have invented certain new and useful Improvements in Electric Barometer-Switches, of which the following plishing any other desired purpose.

turn supported on One object of the invention is to provide improved means for actuating the switch when the temperature risesto the predetermined point. Another object is to provide improved and simplified means for adjusting the switch-so that it may be closed at different temperatures. Other objects will appear as the description proceeds.

The invention will be first hereinafter de-- scribed in connection with the accompanying drawings, which constitute part of this specification, and then more specifically defined in the claims at the end of the description.

. In the accompanying drawings, wherein similar reference characters are used to designate corresponding parts throughout the several views:

Figure 1 is a broken central vertical section through the casing of the switch, showing the U-shaped frame in side elevation.

Fig. 2 is a broken central vertical section taken at right angles to the section of Fig. 1.

Fig. 3 is a detailed perspective "16W. of the spring which extends between the operating pin and the adjusting screw.

'Fig. 4 is a detailed perspective view of the pivoted switch arm.

Fig. 5 is an enlarged detailed plan View of the outer end portion of the upper arm of the U-shaped frame, and

Fig. 6 is a plan View of the casing for the switch alone. W

As illustrated, the casing 1 may be generally semispherical and skeleton in form. On the inside of the casing a lug 2 supports an insulating block 3 by meansof one or more screws l, Fig. 1. A U-shaped frame 5 IS in the insulating block by one or more screws 6. The arms 7 and 8 of the frame 5 extendhorizontally to a' position about centrally of the casing. The lower arm 7 supports a cylindrical reservolr 9 by means .of a clamping strap 11 which embraces the reservoir and is secured to the end of the arm 7 by screws 12. The reservoir 9 opens into a diaphragm 10 positioned between the two arms of the frame 5. The reservolr 1s adapted to hold a quantity of alcohol which may be poured into it when the device is inverted through an opening normally closed by the plug 13.

The upper arm 8 of the frame 5 has a pair of spaced upwardly extending lugs 11 near its end, and a lateral extension 15 intermediate of said lugs. The extension 15 has 'a vertical passage 16 therein arranged in line with the'vertical axis of the diaphragm 10. A pin 17 is fitted to reciprocate in the passage 16 and rest at its base upon the top of the diaphragm. The lugs-11 have lateral offsets 18 extending in the opposite direction from the projection 15 and arranged in a plane above said projection 15. These offsets 18 of the lugs 11 carry pivot screws 19 engaging sockets 21 in the side of the contact lever 20, whereby said lever is pivotally supported with its inner end in vertical alinement with the pin 17. The innerend of said contact arm 20 has a vertical screw-threaded passage 22 therein and in said passage there is fitted an adjusting screw 23. To insure a proper action of the pin 17 upon the adjusting screw 23, a plate spring 26 is placed between them. This plate spring 26 is bifurcated at one end to form parallel spaced fingers 27 adapted to embrace the reduced outer end portion 29 of the contact arm20. The fingers 27 are curved, as shown in Figs.

2 and 3, and the plate spring 26 is held in position by having a cross pin 28 passed uiider the curved fingers 2'7 and above the reduced end portion-29' of the contact arm, as illustrated in Fig. 2.

The contact plate 32 is mounted on an insulating block 31 preferably arranged in a radially ofiset portion 30 of the ca'singl, said contact plate 32 extending into the path of the outer end of the contact arm 20. Said contact arm is normally supported with its I outer end out of contact with the plate 32 by a spring 33.

vAs illustrated diagrammatically m Fig. 2,

may be electrically connected to one pole of a battery 36, while the other pole of the bata xvii-e34: may be connected to the U-shaped tery may be connectedto the contact plate 32 by'a wire thus providing an alarm circuit which will be closed when the outer endfillt) oi the contact arm 20 contacts with the plate 32. It will be understood, of course, that any other circuit, with or without an alarm, may be connected up with the switch to be closed thereby as herein described. p

in operation, if the screw 23 has been set for closing the circuit at a temperature of 150 F2, for instance, as the temperature approaches that point the volatilized alcohol in the reservoir 9 and diaphragm 10 will act upon the diaphragm to raise the in 17 which as it protrudes abovethe pro ection 1-5 comes in contact with the end portion. of the plate spring 26, raising it against the lower end of the adjusting s new 23 and in raising said adjusting screw swings the contact arm 20 on its pivots l9 and brings the outer end portion 29 of said arm down into contact with the plate 32 thereby closing the circuit at the predetermined temperature. By turning the adjusting screw 23 downward, the switch may be set for closing at a lower temperature, while an upward adjustment of said screw will set the switch for operation at a higher temperature. The arrangement of the plate spring :26 between the pin 17 and screw 28 always insures a proper contact as the pin 17 rises. If it were not for this plate spring, the pin 17 might glance ofl of. the lower end of the adjusting screw asthe latter is swung upward with the contact arm under the upward impulse given to the pin 17 by the expanding diaphragm. 'To preserve the proper insulation of the casing l, the same is provided with an enlarged passage for the adjusting screw 23 in its top, and said passage is partially closed by a plate 24 of insulating mazcaiaere a pin seated upon the diaphragm and adapted to act upon the contactarm through the ad usting screw for moving said arm mto contact with the fixed contact at a prede termined temperature, guiding means for restricting the pin to a vertical movement, and a plate spring extending between sald adjusting specified.

2. In an electric switch, the combination with a fixed contact, of a pivoted contact arm, means for normally holding said arm away from the fixed contact, a diaphragm containing a readily Volatilizing liquid, an adjusting screw carried bythe contact arm, a pin seated upon the diaphragm and adapted to act upon the contact arm through the adjusting screw for moving said arm into contact with the fixed contact at a predetermined temperature, guiding means for restricting the pin to a vertical movement, :1 plate spring extending between the adjusting screw and pin for the purpose specified and having curved spaced fingers at its end to embrace the contact arm, and a cross pin to fit below said curved fingers and above the arnrfor supporting the plate spring in position.

In testimony whereof I have signed my name to this specification.

. PETER ERNEST STOFT.

screw and pin for the purpose 

